1. Field of the Invention
The present invention relates to an ultrasound probe and an ultrasound diagnostic imaging apparatus.
2. Description of Related Art
A typical ultrasound diagnostic imaging apparatus scans the interior of a subject with ultrasound waves and creates an image showing the interior on the basis of reception signals generated in response to the reflected ultrasound waves from the subject.
The ultrasound diagnostic imaging apparatus has an ultrasound probe emitting and receiving ultrasound waves to and from the subject.
With reference to FIG. 11, the ultrasound probe includes a plurality of transducers 200 arrayed in the scanning direction, for example. The transducers 200 are formed by bonding a piezoelectric layer (plate) 71, which includes two electrodes having opposite polarities, to a backing layer 73, which reflects, attenuates, and absorbs ultrasound waves directed backward, via a connecting conductor 72, which has conductive patterns 72a arrayed at predetermined intervals in the scanning direction, with an adhesive; and forming slits (primary slits) 74 in the bonded stack at predetermined intervals in such a way that the stack is divided into rectangular plates. The primary slits 74 extend from the piezoelectric plate 71 to the upper portion of the backing layer 73. The primary slits 74 each coincide with the gap between two adjacent conductive patterns 72a. 
Each of the transducers 200 has a slit (secondary slit) 75 having a depth substantially identical to that of the primary slits 74 to define minute elements (subelements) 201 to improve their oscillation efficiency. The secondary slits 75 extend through the conductive patterns 72a. 
Unfortunately, such strip subelements 201 may tilt by the loads (indicated by reference signs T in FIG. 11) thereon during the forming process.
Japanese Unexamined Patent Application Publication No. H11-276479, for example, discloses a technique to prevent the subelements from tilting, focusing attention on the structural differences in the connecting conductor between the portions of the primary slits and the portions of the secondary slits.
In specific, in the technique disclosed in Japanese Unexamined Patent Application Publication No. H11-276479, the connecting conductor has elongated openings at positions corresponding to the secondary slits so that the portions around the primary slits and the portions around the secondary slits in the connecting conductor are composed of the same material and have the same structure. This structure equalizes mechanical loads on the individual transducers (subelements) during the formation of the secondary slits to those during the formation of the primary slits, preventing the subelements from tilting.
Unfortunately, the technique disclosed in Japanese Unexamined Patent Application Publication No. H11-276479 cannot completely solve the problem of tilted subelements: thinner subelements still may tilt under some conditions during the forming process, for example.
In the technique disclosed in Japanese Unexamined Patent Application Publication No. H11-276479, the adhesive protrudes outside the openings of the conductive patterns on the connecting conductor, which impairs the workability in the processes after the bonding process.